Screw nut-guard.



J. DE R. KIELLAND.

SCREW NUT GUARD. APPLICATION FILED SEPT- 20. 1912.

Patented Nov. 23

w W Mall www mxonm .r'rrrrnn; KIELLAND, or cnarsrmnm, NORWAY, AssIeNon. or. ONE-HALF '10 ALBERT 'rnonn, or HAMBURG, GERMANY.

. scnnw ltUT-GUARD.

Application filed September 20, 1912. Serial 110.721350.

To all whom it may concern:

Be it known that 1, JAKOB- on Rr'rrnn KIELLAND, engineer, a subject of the King of Norway, residing at Sporveisgatan 8, Christiania, Kingdom of Norway,- have invented certain new and useful Improvements in or Relating to Screw Nut-Guards,

of which the following is a specification.

The object of the present invention is to provide an absolutely reliable, cheap and easily manipulated screw nut-guard, which may be used everywhere and which may be also employed as a self-locking nut.

- v The nut-guard according to the present invention consists of a preferably hexagonal thin plate made of steel or another suitable material, with a hole punched through its.

- center. The edge of said hole forms a spiral line when in the same plane, but is bent up in such a inanner that it, formsa helical line which will in. diameter and pitch correspond thread on' theibolt, onto which the guard I is to be screwed. The projection of this exactly with the bottom line of the screw helical line will therefore be a circle the diameter of which isv-equal to the diameter ofthe bolt at the bottom of the thread. The

I edge of the hole is dividedby radialnotches are exemplified. The most simple construe tional form is that shown in-Figuresl to 4;-of these Fig. 1 is atop view of theguard' platelafter the hole has been punched; Fig.x 2 is the-same'view of the; plate after the edge of-the hole has been bent up according into a plurality of' sections which when screwed'into the thread of the bolt will act as locking teeth. :These locking teeth and the plate itselfare preferablyfgiven a" certain degree of spring.-*- A combination of} several-suchplates will form'a nut.

In the accompanying draw ngs three con-.-

str uctional forms of the present invention to the pitch o fthe thread,for instance after it haszbeen screwed on to azbolt, the bolt not being shown; l'Fig. 3- shows the guard plate secured to a ,nut, the .bolt being likewise omitted, and Fig.4 is'a cross section. through the guard plate In Figs. 5 to 8 another 'constructional'form is shown; Here Fig. 51 is-the piinch'ed plate; Fig. 6 istheplate bent up in the suitable manner, Fig. 8 is a I cross section through Fig; 6' and Fig. 7

shows a guard-plate of this-kindon a nut,

the bolt being here also shown, F igs. 9- to 11 show a top view, side view and cross secs m n manate. FatentedNov.23,1915.

tion of a self-locking nut-composed of a'plurality of such plates.

The guard, Fig. 1, consists of a preferof which depends on the diameter and the pitch of the screw bolt, on which the guard is to be used. This spiral line will namely correspond to the curve which is obtained ably hexagonal steel plate P, in .which'a h ole L is punched. The edge H of this hole ,which contains a number of-radial notches i, has the shape of a spiral line, the. shape.

by plottingv and its length: will equal the length of the bottom line of one turn of the.

thread into a plane. When the guard plate according to Fig. 1 is screwed on a bolt,the" .mtegral portions of the edge of said hole will force deep into the bottom of the thread and will thus form a turn of the samethread which seen in a vertical projection will correspond to the shape ofthe hole shown'in Fig." 2. Here the edge H of the hole forms a circle, the diameter ofwhich is equal to the diameter of the bottom of the thread on the bolt. The teeth 'A projeeting between the notches '21 in the edge of said holeL will press tightly into the :thread and when the plateis screwed down tightly, they will. act

tegral portions of said margin will fit and .be strongly pressed against'the' root of the bolt thread and, in consona'nce with the laws governing theelastic reactions of metals,

will slightly compress those portions of the;

bolt with which they are in contact, which movement of the molecules of the bolt 'will' cause an engagement between the said'bolt and nut-lock, of such a nature as to resist a all known vibratory and nut-loosening forces. Thus the plate L 'is' itselfflockedf and locks the nut to the bolt through the increased friction and at the same time permits removal of the nut-lock L should circumstances require the removal of the nut.

It is also advisable to bend up the plate P at its outside edges as well, as shown in Figs. 3 and 4, so as to give it a certain degree of spring. This gives the plate a greater stiffness and at the same time the gripping of the plate with the screw wrench is facilitated, while its bearing surface in contact with the nut (Min Fig. 3) is smaller, so that it can be more easily loosened by hand when desirable.

With the constructional form shown in Figs. 5 to 8 the guard plate has besides the inward elastic teeth punched out of the spiralline alsovelastic tongues B- on the outside. edge. Fig. 5 shows the plate immediately after it has been punched out. These outer tongues A are subsequently bent upward and inward toward the screw bolt, extendingin a radial direction, as shown in Figs. 6 to 8. The sharp edges of these hardened tongues will then bear against the thread of the bolt in a direction contrary to that in which the guard is tightened and will also prevent the guard from accidentally getting loose. These outside tongues will under certain conditions greatly improve the effect of the guard according to Figs. 1 to 4. Of course the guard would also be effective if it were provided with the outer tongues B only.

According to Figs. 9 to 11 a more or less large number of such plate guards according to Figs. 1 to 4 are-placed on each other at a distance equal to the pitch of the thread and pressed into a common nut-like case G. Thereby a self-locking nut is obtained, which has a practically elastic female thread. The distance at which the guard plates are arranged, may be either equal to the single pitch of the thread or only every second or third turn of the thread is utilized, and so on, by intermediate packings Z of ,a suitable thickness being employed, which must of course have the necessary strength.

The efi'ect of all the constructional forms of the guard hereinbefore described depend on the great moment compared to the small mass of the plate or ring, with which the spring locking teeth are obliged to press against the screw thread when the guard is tightened against abacking. It is further essential that'all spring teeth engage simultaneously in the thread. The elastic pressure against the backing is of a further advantage.

It may be here mentioned that screw guards have already been suggested, which consisted of an elastic plate having a circular bore and intended to be screwed on the screw bolt. The present invention differs from these known guards, which all showed constructional defects and have not found any extensive use in practice, above all in that the hole is punched in such a manner that its edge forms an interrupted helix or female screw thread whose integral portions lit and are in elastic co-action with the bottom of the bolt thread, the teeth formed by said interrupted helix engaging with the root of the thread of the bolt with increasing friction, said frictional engagement with the root of the thread being in direct ratio to the force with which the nut lock L is screwed down on the nut.

' What I claim as my invention and pray to secure by Letters-Patent is 1. A nut lock comprising a metal plate having a bolt hole comprising a straight portion that is substantially radial to the center of the bolt hole and a single spiral convolution starting and terminating at said straight portion, there being a plurality of substantially radial notches in said plate extending inwardly from said bolt hole, said notches being progressively one longer than the other, the shortest notch being disposed at said straight portion and the continuation of said straight portion forming one side of said shortest notch, and .the longest notch being disposed adjacent to said shortest notch, said notches forming a plurality of broad teeth in said plate extending toward an imaginary line centrally of said bolt hole, said teeth being progressively one longer than the other, the shortest tooth and the longest tooth being disposed adjacent to one another, the teeth being disposed in a helical path with the shortest tooth at one end of the helical path and the longest tooth at the other end of such helical path, and the teeth being each bent at a different angle to a certain plane, that is, beginning with the next to the shortest tooth, the teeth are each bent at an angle one progressively greater than the angle of its preceding tooth so that all the active edges of the teeth will terminate in an imaginary cylindrical surface, the entire broad active edges of the teeth forming a spiro-helical line only interrupted by said notches.

2. A nut lock comprising a disk of elastic metal having a bolt hole therein, a plurality of teeth in said disk extendin toward an imaginary line centrally of said bolt hole, said teeth being progressively one longer tha'i the other, the shortest tooth and the 101 gest tooth being disposed adjacent to one another, the teeth being bent at different angles to a certain plane that is, beginning with the next to the shortest tooth, the teeth are each bent at an angle one progressively greater than the angle of its preceding tooth so that all the inner edges of the teeth Will terminate in an imaginary cylindrical surface, and flanges on the outer edges of said disk, portions of said flanges extending radially inward to form stifl'ening means for the disk.

In Witness whereof I have hereunto signed my name this 6 day of September, 1912, in the presence of two subscribing Witnesses.

J AKOB DE RYTTER KIELLAND.

Witnesses M. GUTTODUSKY, SIGM. B611. 

